Computers can be used to generate a wide variety of electronic documents, records, and files. Frequently, the user may desire to have a hardcopy of an electronic document. Consequently, printers have been developed that can receive electronic data from a host computer and produce a hardcopy of the electronic document represented by that data. This includes such printing devices as laser printers, inkjet printers, plotters, facsimile machines, digital copiers, and the like.
Traditional printing operations entail a number of data language conversions as the print job progress from an electronic application data file to a printed hardcopy. Initially, the data for the electronic document is converted into a page description language (PDL) to aid in the transmission of the image data from the host computer to a printing device. This data is then sent from the host computer to a printing device through an Input/Output (I/O) port of the printing device.
Once the printing device receives the image data, likely written in a PDL, the information is converted to an intermediate form called a display list. A display list is a list of display commands that define graphic elements and their contexts within the image to be printed. These display commands are usually one of the three following types: characters or text, line drawings (also referred to as vectors), and images (also referred to as raster data).
The display list is an intermediate step in the processing of the image data. The display list is then parsed and converted into a final form. This conversion is known as rasterizing the image data. Once rasterized, the image data is sent to the print engine controller for processing and forming of the desired image on a print medium, such as paper.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.